Albert Einstein: "The supreme goal of all theory is to make the irreducible basic element as simple and as few as possible without having to surrender the adequate representation of a datum of experience." 

Hitler explains his justification for the Final Solution:

Nature if cruel. Therefore, we too, may be cruel. If I don’t mind sending the pick of the German people into the hell of war without regret for the shedding of valuable German blood, then I have naturally the right to destroy millions of men of inferior races who increase like vermin. (Meltzer, 197

I've come across passages similar to this one again and again in Hitler's speeches. Hitler was saying that if he had no compunction about sending his own soldiers to their deaths (doing so without regret), why should he not also have the right to send Jews to their deaths?

This was Hitler's logic--the logic of the Final Solution. The logic of the Holocaust followed from the logic of warfare. If warfare (sending one's own soldiers to die) is conceived as "normal," why should sending Jews to die be conceived as abnormal?